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541d21da4dfd9dddb1168cfdd18b2ce10e8f023b
[etc/vim.git] / tests / util.py
1 import os
2 import sys
3 import unittest
4 from contextlib import contextmanager
5 from dataclasses import replace
6 from functools import partial
7 from pathlib import Path
8 from typing import Any, Iterator, List, Optional, Tuple
9
10 import black
11 from black.debug import DebugVisitor
12 from black.mode import TargetVersion
13 from black.output import diff, err, out
14
15 from . import conftest
16
17 PYTHON_SUFFIX = ".py"
18 ALLOWED_SUFFIXES = (PYTHON_SUFFIX, ".pyi", ".out", ".diff", ".ipynb")
19
20 THIS_DIR = Path(__file__).parent
21 DATA_DIR = THIS_DIR / "data"
22 PROJECT_ROOT = THIS_DIR.parent
23 EMPTY_LINE = "# EMPTY LINE WITH WHITESPACE" + " (this comment will be removed)"
24 DETERMINISTIC_HEADER = "[Deterministic header]"
25
26 PY36_VERSIONS = {
27     TargetVersion.PY36,
28     TargetVersion.PY37,
29     TargetVersion.PY38,
30     TargetVersion.PY39,
31 }
32
33 DEFAULT_MODE = black.Mode()
34 ff = partial(black.format_file_in_place, mode=DEFAULT_MODE, fast=True)
35 fs = partial(black.format_str, mode=DEFAULT_MODE)
36
37
38 def _assert_format_equal(expected: str, actual: str) -> None:
39     if actual != expected and (conftest.PRINT_FULL_TREE or conftest.PRINT_TREE_DIFF):
40         bdv: DebugVisitor[Any]
41         actual_out: str = ""
42         expected_out: str = ""
43         if conftest.PRINT_FULL_TREE:
44             out("Expected tree:", fg="green")
45         try:
46             exp_node = black.lib2to3_parse(expected)
47             bdv = DebugVisitor(print_output=conftest.PRINT_FULL_TREE)
48             list(bdv.visit(exp_node))
49             expected_out = "\n".join(bdv.list_output)
50         except Exception as ve:
51             err(str(ve))
52         if conftest.PRINT_FULL_TREE:
53             out("Actual tree:", fg="red")
54         try:
55             exp_node = black.lib2to3_parse(actual)
56             bdv = DebugVisitor(print_output=conftest.PRINT_FULL_TREE)
57             list(bdv.visit(exp_node))
58             actual_out = "\n".join(bdv.list_output)
59         except Exception as ve:
60             err(str(ve))
61         if conftest.PRINT_TREE_DIFF:
62             out("Tree Diff:")
63             out(
64                 diff(expected_out, actual_out, "expected tree", "actual tree")
65                 or "Trees do not differ"
66             )
67
68     if actual != expected:
69         out(diff(expected, actual, "expected", "actual"))
70
71     assert actual == expected
72
73
74 class FormatFailure(Exception):
75     """Used to wrap failures when assert_format() runs in an extra mode."""
76
77
78 def assert_format(
79     source: str,
80     expected: str,
81     mode: black.Mode = DEFAULT_MODE,
82     *,
83     fast: bool = False,
84     minimum_version: Optional[Tuple[int, int]] = None,
85 ) -> None:
86     """Convenience function to check that Black formats as expected.
87
88     You can pass @minimum_version if you're passing code with newer syntax to guard
89     safety guards so they don't just crash with a SyntaxError. Please note this is
90     separate from TargetVerson Mode configuration.
91     """
92     _assert_format_inner(
93         source, expected, mode, fast=fast, minimum_version=minimum_version
94     )
95
96     # For both preview and non-preview tests, ensure that Black doesn't crash on
97     # this code, but don't pass "expected" because the precise output may differ.
98     try:
99         _assert_format_inner(
100             source,
101             None,
102             replace(mode, preview=not mode.preview),
103             fast=fast,
104             minimum_version=minimum_version,
105         )
106     except Exception as e:
107         text = "non-preview" if mode.preview else "preview"
108         raise FormatFailure(
109             f"Black crashed formatting this case in {text} mode."
110         ) from e
111     # Similarly, setting line length to 1 is a good way to catch
112     # stability bugs. But only in non-preview mode because preview mode
113     # currently has a lot of line length 1 bugs.
114     try:
115         _assert_format_inner(
116             source,
117             None,
118             replace(mode, preview=False, line_length=1),
119             fast=fast,
120             minimum_version=minimum_version,
121         )
122     except Exception as e:
123         raise FormatFailure(
124             "Black crashed formatting this case with line-length set to 1."
125         ) from e
126
127
128 def _assert_format_inner(
129     source: str,
130     expected: Optional[str] = None,
131     mode: black.Mode = DEFAULT_MODE,
132     *,
133     fast: bool = False,
134     minimum_version: Optional[Tuple[int, int]] = None,
135 ) -> None:
136     actual = black.format_str(source, mode=mode)
137     if expected is not None:
138         _assert_format_equal(expected, actual)
139     # It's not useful to run safety checks if we're expecting no changes anyway. The
140     # assertion right above will raise if reality does actually make changes. This just
141     # avoids wasted CPU cycles.
142     if not fast and source != actual:
143         # Unfortunately the AST equivalence check relies on the built-in ast module
144         # being able to parse the code being formatted. This doesn't always work out
145         # when checking modern code on older versions.
146         if minimum_version is None or sys.version_info >= minimum_version:
147             black.assert_equivalent(source, actual)
148         black.assert_stable(source, actual, mode=mode)
149
150
151 def dump_to_stderr(*output: str) -> str:
152     return "\n" + "\n".join(output) + "\n"
153
154
155 class BlackBaseTestCase(unittest.TestCase):
156     def assertFormatEqual(self, expected: str, actual: str) -> None:
157         _assert_format_equal(expected, actual)
158
159
160 def get_base_dir(data: bool) -> Path:
161     return DATA_DIR if data else PROJECT_ROOT
162
163
164 def all_data_cases(subdir_name: str, data: bool = True) -> List[str]:
165     cases_dir = get_base_dir(data) / subdir_name
166     assert cases_dir.is_dir()
167     return [case_path.stem for case_path in cases_dir.iterdir()]
168
169
170 def get_case_path(
171     subdir_name: str, name: str, data: bool = True, suffix: str = PYTHON_SUFFIX
172 ) -> Path:
173     """Get case path from name"""
174     case_path = get_base_dir(data) / subdir_name / name
175     if not name.endswith(ALLOWED_SUFFIXES):
176         case_path = case_path.with_suffix(suffix)
177     assert case_path.is_file(), f"{case_path} is not a file."
178     return case_path
179
180
181 def read_data(subdir_name: str, name: str, data: bool = True) -> Tuple[str, str]:
182     """read_data('test_name') -> 'input', 'output'"""
183     return read_data_from_file(get_case_path(subdir_name, name, data))
184
185
186 def read_data_from_file(file_name: Path) -> Tuple[str, str]:
187     with open(file_name, "r", encoding="utf8") as test:
188         lines = test.readlines()
189     _input: List[str] = []
190     _output: List[str] = []
191     result = _input
192     for line in lines:
193         line = line.replace(EMPTY_LINE, "")
194         if line.rstrip() == "# output":
195             result = _output
196             continue
197
198         result.append(line)
199     if _input and not _output:
200         # If there's no output marker, treat the entire file as already pre-formatted.
201         _output = _input[:]
202     return "".join(_input).strip() + "\n", "".join(_output).strip() + "\n"
203
204
205 def read_jupyter_notebook(subdir_name: str, name: str, data: bool = True) -> str:
206     return read_jupyter_notebook_from_file(
207         get_case_path(subdir_name, name, data, suffix=".ipynb")
208     )
209
210
211 def read_jupyter_notebook_from_file(file_name: Path) -> str:
212     with open(file_name, mode="rb") as fd:
213         content_bytes = fd.read()
214     return content_bytes.decode()
215
216
217 @contextmanager
218 def change_directory(path: Path) -> Iterator[None]:
219     """Context manager to temporarily chdir to a different directory."""
220     previous_dir = os.getcwd()
221     try:
222         os.chdir(path)
223         yield
224     finally:
225         os.chdir(previous_dir)